Essential Oil of Sage. 343 



The followino- are the results of a Vtapour-density deter- 

 mination of this liquid : — 



Height of barometer =758 millims. 



Temperature of air = 18°. 



Height of mercury column in barometer-tube =511 millims. 



Temperature of vapour =185°. 



Tension of mercury vapour at 185° =12 millims. 



Weight of mercury required to occupy space formerly 



occupied by vapour = 874*7 grams. 

 Temperature of mercury =20°. 

 Hence, volume of vapour =64'61 cubic centims. 

 Weight of liquid =0-0804 gram. 

 Weight of volume of hydrogen equal to volume of vapour 



under same conditions of temperature and pressure = 



0-001129 gram. 



Hence -k ^ .nn-j-ioQ =71-2. Calculated =^^. 



Two experimentSj in addition to that the results of which 

 are detailed, were carried out ; but in each a small quantity of 

 air found its way into the barometer-tube ; the results were 

 therefore too low. In every case a small quantity of brown 

 resinous matter remained in the small bottle unvolatilized; hence 

 it appears either that the terpene contained a small quantity of 

 a substance boiling very considerably above 185°, or that the 

 action of such an amount of heat as is represented by this 

 temperature exerted a decomposing (polymerizing?) action 

 upon the terpene. The presence of 4 per cent, of a terpene 

 of the formula Ci., H24, supposing this to remain completely 

 unvolatilized, would bring the observed vapour-density to 68*3, 

 which is almost identical with the calculated number. 



12. The specific gravity of the terpene boiling at 167° to 168^ 

 was 0-8866 at 15°. 



We are again indebted to the kindness of Dr. Gladstone 

 for determinations of the refractive indices of this terpene. 



fiK =1-4588, fjuD =1-4646, /xH =1*4830, at 24°-5. 



Hence, specific refractive energy =0-0522, and 



Refraction equivalent =71*0. 



13. Dr. Tilden has been so good as to examine the action 

 of nitrosyl chloride upon this terpene. He says, " I could 

 get no so id products from this liquid. The action of the gas 

 caused effervescence immediately ; and this is always a bad 

 sign. I suspect this to be a mixture containing a hydro- 

 carbon of the Ci5 H24 type. I never got any solid compounds 



